Abstract: The experiment adopts oesophageal infusion with large dose DL242 3H 2Phe to research protein synthesis metabolism in whole body , muscle and hepatopancreas of 20 ～30g grass carp in different essential amino acid (EAA) patterns. The results show that : 1. Four imbalance EAA patterns , respectively short of Lys 、 Met 、Trp 、Arg , compared with EAA pattern of muscle , result in remarkable fractional protein synthesis rate (FSR) decrease of muscle , hepatopancreas and whole body , which shows the decreasing by Met > Lys > Arg > Trp. 2.Followingthevariationof EAApattern, FSRof muscle, hepatopancreasandwholebodyhasasimilar change , and shows FSR by : hepatopancreas > whole body > muscle. 3. In Met ,Lys ,Arg and Trp four factors of EAA pattern , from Met to Trp have gradually and orderly weakened impact on protein synthesis in muscle and hepatopancreas of grass carp , in other words , Met has the largest impact .